CN205427525U - MBUS calorimeter data acquisition controller receiving circuit - Google Patents

Abstract

The utility model provides a MBUS calorimeter data acquisition controller receiving circuit, comprising an one -chip microcomputer, be connected with divider resistance R13 at the MBUS signal reception end, MBUS received the current signal through divider resistance R13 after pin AD_1 inserts the singlechip, be connected with DA circuit analog output voltage on the SPI of singlechip interface, analog voltage inserts voltage comparater LM2903's IN+ end, the MBUS signal reception end still is connected with sampling resistor R15, sampling resistor R15's other end ground connection, does the MBUS signal reception end get into voltage comparater LM2903's IN behind resistance R18 the end. This receiving circuit can not arouse data signal's distortion and in disorder because of the change of load.

Description

A kind of MBUS Calorimeter data acquisition controller receives circuit

Technical field

The utility model relates to a kind of controller and receives circuit, receives circuit particularly to a kind of MBUS calorimeter data acquisition controller, belongs to control technical field.

Background technology

Energy-saving and emission-reduction are that the Major Strategic of country is disposed.Heat supply in winter consumes a large amount of heat energy, and the past uses the Scientific Measurement being not suitable with the energy by the metering method of area charge, wastes substantial amounts of energy consumption.Firmly build now portion's installation at popularization family, whole nation calorimeter, carry out the on-demand use of heat, multiplex spend more, need not spend, promoting the efficient utilization to heat energy, the central heating of current China, heating system meterage gradually spread out, and metering device main in thermal substation is exactly calorimeter.Calorimeter is a kind of electromechanical integration instrument based on microprocessor and high-precision sensor, the gauge table commonly used in the past with building industry, and such as water meter, ammeter, gas meter are compared, and it has more complicated design and higher technology content.Calorimeter passes through temperature and two kinds of sensors of flow, records heat carrier respectively at the temperature imported and exported and flow, then obtains calorie value through density and the compensation of heat enthalpy value and integral and calculating.Meter bus MBus(Meter-Bus) it is a kind of bus protocol exclusively for the design of calorimeter remote data transmission, it is a kind of important technology that measuring instruments data are transmitting digitized, have been widely used for heat metering field, and become a part (European standard EN1434-3) for the heat metering standard in Europe.MBus receives circuit and is to ensure that its basis normally worked, it is the electric current loop received when traditional MBUS calorimeter data acquisition control receives signal, common practice is all the method using complete hardware comparator, this method is practical when load impedance is consistent and load change is little, but calorimeter may be from different producers in actual applications, there is different impedances, and calorimeter is owing to safeguarding, stop, the reasons such as unlatching often cause the change of load impedance, owing to the load curent change that causes of change is more than receiving curent change that electric current causes greatly, so directly affecting DC Level Shift, cause signal waveform distortion.

Summary of the invention

The purpose of this utility model is to overcome MBUS calorimeter data acquisition controller in prior art to receive the problems referred to above that circuit exists, it is provided that a kind of MBUS calorimeter data acquisition controller receives circuit.

nullFor realizing the purpose of this utility model，Have employed following technical scheme: a kind of MBUS calorimeter data acquisition controller receives circuit，Including single-chip microcomputer，Connect at MBUS signal receiving end and have divider resistance R13，MBUS receives current signal and accesses single-chip microcomputer through pin AD_1 after divider resistance R13，The SPI interface of single-chip microcomputer connects and has D/A circuit to export analog voltage，Analog voltage accesses the IN end of voltage comparator LM2903，MBUS signal receiving end is also associated with sampling resistor R15，The other end ground connection of sampling resistor R15，MBUS signal receiving end enters the IN end of voltage comparator LM2903 after resistance R18，When MBUS signal receiving end has signal，The pressure drop of certain value is become under the effect of divider resistance R13，After single-chip microcomputer, single-chip microcomputer knows for sure and receives the size of signal value，Single-chip microcomputer exports an analog voltage to the IN+ end of voltage comparator LM2903 according to the size of the signal value received from SPI interface，MBUS signal receiving end enters the IN end of voltage comparator LM2903 after resistance R18 and compares simultaneously，Signal inputs to single-chip microcomputer from the IOUT interface of voltage comparator LM2903，Further，The other end of divider resistance connects resistance R14，The other end ground connection of R14，The plus earth of diode D3，Negative pole is connected in the AD_1 input of single-chip microcomputer，Further，Described sampling resistor R15=20 Ω，Resistance R18=20k Ω，Resistance R13=10k Ω，Electric capacity C16 it is also connected with between MBUS signal receiving end and ground connection，Electric capacity C16=0.01 F，Further，Resistance R14=10k Ω，Further，The D/A circuit connected on the SPI interface of described single-chip microcomputer is MCP4801 chip.

Positive Advantageous Effects of the present utility model is: the utility model uses single-chip microcomputer first to detect the size of signal; then transport to voltage comparator according to the size corresponding analog voltage of output of signal compare; ensure that and remain able to reliable output signal when load changes; distortion and the entanglement of data-signal will not be caused because of the change of load; moreover detect signal by single-chip microcomputer by A/D end; when being short-circuited; single-chip microcomputer can be immediately detected, and coordinates corresponding protection circuit to can ensure that the safe operation of whole system.

Accompanying drawing explanation

Fig. 1 is reception circuit theory diagrams of the present utility model.

Fig. 2 is the electrical schematic diagram of single-chip microcomputer output transform analog voltage of the present utility model.

Detailed description of the invention

In order to explain enforcement of the present utility model more fully, it is provided that embodiment of the present utility model.These embodiments are only to elaboration of the present utility model, are not intended to scope of the present utility model.

In conjunction with accompanying drawing, the utility model is carried out further details of explanation, Fig. 1, Fig. 2 are all shown without single-chip microcomputer, the pin that AD_1 pin is on single-chip microcomputer in FIG, TX1 output is also to single-chip microcomputer, in Fig. 2, the CS interface in SPI interface, i.e. figure, SCK interface, SDI interface.nullAs shown in drawings，A kind of MBUS calorimeter data acquisition controller receives circuit，Including single-chip microcomputer，Connect at MBUS signal receiving end and have divider resistance R13，R13=10kΩ，MBUS receives current signal and accesses Chip Microcomputer A/D conversion after divider resistance R13，The pin that in Fig. 1, AD_1 pin is on single-chip microcomputer，What single-chip microcomputer recorded is exactly the pressure drop of AD_1 pin，The SPI interface of single-chip microcomputer connects and has D/A circuit to export analog voltage，In Fig. 2, MCP4801 chip is D/A conversion chip，The analog voltage of MCP4801 output exports from ADJUST-V end，Analog voltage accesses the IN+ end of voltage comparator LM2903，MBUS signal receiving end is also associated with sampling resistor R15，Sampling resistor R15=20 Ω，The other end ground connection of sampling resistor R15，MBUS signal receiving end enters the IN end of voltage comparator LM2903 after resistance R18，R18=20K，When MBUS signal receiving end has signal，The pressure drop of certain value is become under the effect of divider resistance R13，After Chip Microcomputer A/D conversion, single-chip microcomputer knows for sure and receives the size of signal value，Single-chip microcomputer exports an analog voltage to the IN+ end of voltage comparator LM2903 according to the size of the signal value received from SPI interface，By sampling resistor, the electric current loop of signal is transformed to Voltage loop，MBUS signal receiving end enters the IN end of voltage comparator LM2903 after resistance R18 and compares simultaneously，Signal inputs to single-chip microcomputer from the IOUT interface of voltage comparator LM2903，The other end of divider resistance R13 connects resistance R14，R14=10kΩ，The other end ground connection of resistance R14，The plus earth of diode D3，Negative pole is connected in the AD_1 input of single-chip microcomputer，Foregoing circuit also forms the protection circuit to single-chip microcomputer，Electric capacity C16 it is also connected with between MBUS signal receiving end and ground connection，Electric capacity C16=0.01 F.nullDuring utility model works，The pressure drop that first single-chip microcomputer is formed on divider resistance according to signal detects the definite size of signal after A/D changes，Then export corresponding voltage according to the size of signal to be converted to analog voltage through D/A conversion chip and transport to voltage comparator and compare，When load changes，Single-chip microcomputer detection to signal value also can change，Because single-chip microcomputer is to control the voltage swing of output on SPI interface according to the signal magnitude detected，Ensure that the reliability that on voltage comparator, two signals compare by this way，The most errorless output signal is remained able to when load changes，Distortion and the entanglement of data-signal will not be caused because of the change of load，Moreover detect signal by single-chip microcomputer by A/D end，If be once short-circuited，Then the level of MBUS receiving terminal can raise rapidly，Single-chip microcomputer can be immediately detected，Coordinate corresponding protection circuit can also ensure the safe operation of whole system.During the work of this circuit, after system electrification, bus is powered from machine calorimeter telecommunication circuit, the reasons such as the characteristic due to the number loaded and load, pressure drop on R15 can be different, and this MBUS reception circuit being also the most current can not correctly copy and accept the reason of data when load characteristic or number change, after this circuit powers on, first measure the voltage between R13 and R14, calculate the voltage of IN+ end 2 pin of comparator LM2903.Then single-chip microcomputer passes through spi bus, control the DA chip MCP4801 output voltage 3 pins to comparator LM2903, and constantly gather the voltage of AD_1 point, 3 pin voltage making comparator LM2903 are more than comparator 2 pin voltage, and are slightly less than the voltage of comparator 2 pin when transmitting digital 0 in bus.This voltage is as the reference voltage of comparator.Reference voltage is different according to the voltage difference of AD_1 point, set up a form and store in single-chip microcomputer memory, in case inquiry, when slave station return current pulse train, change the voltage of comparator 2 pin, by compared with reference voltage, OUT1 pin output voltage pulse train, after level conversion is 0 ~ 5 V signal, the serial ports connecing single-chip microcomputer receives pin RX1, owing to system adjusts the reference voltage of comparator 3 pin in real time according to the voltage of AD_1 point, make this reception circuit adapt to ability to be greatly enhanced, in communication process, because AD_1 point voltage value constantly changes, therefore send data before by bus to calorimeter when concentrator, stop the voltage sample of AD_1 point, after receiving slave station data and returning, restart the voltage sample to AD_1 point.Every 1 S according to the different voltage of AD_1 point, update a reference voltage.The plus earth of Zener diode D3, negative pole is connected in the AD_1 input of single-chip microcomputer, and foregoing circuit forms protection circuit, the AD_1 input of protection single-chip microcomputer.

After describing embodiment of the present utility model in detail, one of ordinary skilled in the art is clearly understood that, various change and amendment can carried out under spirit without departing from above-mentioned claim, all any simple modification, equivalent variations and modifications above example made according to technical spirit of the present utility model, belong to the scope of technical solutions of the utility model, and the utility model is also not only restricted to the embodiment of example in specification.

Claims (5)

1. null1. a MBUS calorimeter data acquisition controller receives circuit，Including single-chip microcomputer，It is characterized in that: connecting at MBUS signal receiving end has divider resistance R13，MBUS receives current signal and accesses single-chip microcomputer through pin AD_1 after divider resistance R13，The SPI interface of single-chip microcomputer connects and has D/A circuit to export analog voltage，Analog voltage accesses the IN end of voltage comparator LM2903，MBUS signal receiving end is also associated with sampling resistor R15，The other end ground connection of sampling resistor R15，MBUS signal receiving end enters the IN end of voltage comparator LM2903 after resistance R18，When MBUS signal receiving end has signal，The pressure drop of certain value is become under the effect of divider resistance R13，After single-chip microcomputer, single-chip microcomputer knows for sure and receives the size of signal value，Single-chip microcomputer exports an analog voltage to the IN+ end of voltage comparator LM2903 according to the size of the signal value received from SPI interface，MBUS signal receiving end enters the IN end of voltage comparator LM2903 after resistance R18 and compares simultaneously，Signal inputs to single-chip microcomputer from the IOUT interface of voltage comparator LM2903.
2. A kind of MBUS calorimeter data acquisition controller the most according to claim 1 receives circuit, it is characterized in that: the other end of divider resistance R13 connects resistance R14, the other end ground connection of R14, the plus earth of diode D3, negative pole is connected in the AD_1 input of single-chip microcomputer.
3. A kind of MBUS calorimeter data acquisition controller the most according to claim 1 receives circuit, it is characterized in that: described sampling resistor R15=20 Ω, resistance R18=20k Ω, resistance R13=10k Ω, electric capacity C16, electric capacity C16=0.01 F it is also connected with between MBUS signal receiving end and ground connection.
4. A kind of MBUS calorimeter data acquisition controller the most according to claim 1 receives circuit, it is characterised in that: resistance R14=10k Ω.
5. A kind of MBUS calorimeter data acquisition controller the most according to claim 1 receives circuit, it is characterised in that: the D/A circuit connected on the SPI interface of described single-chip microcomputer is MCP4801 chip.